Many recombinant therapeutic biopharmaceutical products are produced in mammalian cell cultures such as Chinese Hamster Ovary (CHO) cells. Mammalian cell cultures are preferred over other expression systems such as yeast and prokaryotic systems for the production of recombinant glycoproteins, largely because the mammalian cell cultures produce glycoproteins with glycosylation patterns that are generally recognized and tolerated by humans.
The potentially adverse effects of terminal alpha-linked galactose (gal-α-1,3-gal) linkages are known Chung et al., N Engl J Med, 358:11 (2008). It has been previously reported that such terminal alpha-gal linkages are not present in recombinant glycoproteins produced by Chinese Hamster Ovary (CHO) cells. For example, while an anti-CDw52 antibody, Campath, produced in NSO, a murine-developed myeloma cell line, includes potentially immunogenic glycoforms having nonreducing terminal alpha-linked galactose residues, Campath produced from CHO cells contained primarily three glycoforms which are consistent with normal human IgG. Sheeley et al., Analytical Biochemistry 247:102-110 (1997).